1. Field of the Invention
This invention relates generally to air filters used to filtrate and clean the air of contaminants, and more particularly, the present invention relates to a multi-sectioned filter, which has different media to remove different types of contaminants from the outdoor supply air, before entering the occupied spaces of large buildings, via heating, ventilating and air conditioning (HVAC) systems.
2. Description of the Prior Art
As Americans, Chinese, Indians, and the world in general, increasingly consume more gas, coal and other fossil fuels, it is inevitable that unhealthy pollutants will continue to contaminate the atmospheric air. Unfortunately, this trend will persist because the already existing, and the emerging, industrialized countries rely heavily on cars for transportation, manufacturing for consumer products and trucking to deliver those consumer products, to name only a few examples. The pollutant by-products released into the air from the world's energy consumption are not, however, the only contaminants found in the atmospheric air. Particulate material and gases, not only generated from industrial processes, but also generated by nature and by man, are also in the air.
Despite great efforts to clean up the environment, the air is still not very clean because the amount of pollutants released into the air each year far exceeds the beneficial gains made from the clean up effort. Unless and until we, as a world community, change our ways of life, dangerously unhealthy pollutants will undoubtedly contaminate the air we breathe.
This is a major health concern especially for commercial, residential and institutional building owners and managers whose obligation is to provide a high indoor air quality for the building's occupants and tenants. Ironically, during the oil crisis in the mid-1970's, when the building owners and managers tried to save energy by using less outdoor air in the air conditioning systems, the end result was an increase in contaminants within the occupied spaces of the building and a dramatic decrease in overall indoor air quality. These results occurred due to the manner in which heating, ventilating and air conditioning (HVAC) systems operate in large buildings.
In order to circulate air throughout a large building, such as a school or an office building, atmospheric air is drawn into the HVAC system and passes through a series of filters before it reaches the occupied spaces of the building. Because the process of drawing air into the building (and ventilating air out of the building) is relatively expensive, the building managers aim to limit the frequency of this process. So instead of constantly drawing air into the building, the managers re-circulate (a less expensive process) the air that has already been drawn into the building's occupied spaces.
Since most building managers adhere to the notion of conserving energy, and in turn money, the managers continuously re-circulate the air and prolong ventilating the air until it is absolutely necessary. Given this and the fact that the type of pollutants that are filtered out of the air, which are drawn into the building, are limited to the number of filter banks used in the HVAC system, it is important for the manager to correctly identify which type of media filters to use in the system.
Generally, large building filter banks consist of two or more sets of filters. The first stage filters, pre-filters, are located on the outermost section of the HVAC system. The pre-filters are coarse, low-efficiency filters that remove large particles and debris. Although the pre-filters achieve their designed purpose to protect the blowers and other mechanical components of the ventilation system, the pre-filters are not effective in removing submicrometer particles from the air. Thus, the removal of these submicrometer pollutants is dependent on the performance of the additional downstream filters.
As mentioned before, the type of media filter determines the type of pollutant that will be filtered out of the air. There are numerous amounts of media to chose from, some of which are zeolites, alumina and polymer sorbents. However, the most common type of medium used is activated carbon. Activated carbon is the medium most often used because of its ability to be treated with a wide range of different chemicals, which adsorb specific types of pollutants. Carbon, by itself, does not have a great capacity to remove lower boiling point gases (pollutants), but when the carbon is treated with a specific chemical the treated carbon will remove the corresponding type of pollutant. This treatment is commonly referred to as impregnation.
Money conscious managers usually try to cut their budget by using impregnated carbon filters that are only coated with one type of chemical and that remove only the necessary pollutants. Since the entire HVAC system typically has only two to three downstream filters, only two to three different types of pollutants are filtered out of the atmospheric air, leaving other pollutants in the ambient air at the detriment of the building's occupants.
Surprisingly, a single multi-sectioned panel air filter, which has different media, has not been developed and constructed heretofore in the prior art so as to remove different types of contaminants from the outdoor supply air, before entering the occupied spaces of large buildings, via heating, ventilating and air conditioning systems. Because a filter like this is not in the prior art, it would be desirable to provide such a filter device like this in order to improve the air quality in large buildings.
A prior art search directed to the subject matter of this application in the U.S. Patent and Trademark Office revealed the following Letters Patent:
4,578,0915,264,1965,503,8065,956,9446,344,071
In addition to the above issued prior art utility patents, there was also found Patent Application Publication No. 2007/0084168 dated Apr. 19, 2007 to Ashwood et al. and Japanese Patent Publication No. 2004183746 dated Jan. 12, 2006 to Toshifumi et al.
U.S. Pat. No. 6,344,071 to Smith et al. discloses a filter system for filtering contaminants from the air or other gases. The filter system includes a filter canister. Within the filter canister, first plurality of filter media particles are intermixed with second plurality of filter media particles into a single filter bed layer. Alternatively, Smith also teaches that two kinds of filter media particles can be positioned in separate filter bed layers as illustrated in FIG. 2. Thus, within the filter canister, first plurality of filter media particles is positioned in the first filter bed and the second plurality of filter media particles is positioned in the second filter bed. Both examples filter multiple types of gases.
In U.S. Pat. No. 4,578,091 to Borja a multi-chambered air cleaner is disclosed. Although the air cleaning device is adapted for use in conjunction with an internal combustion engine to remove particulate matter emitted from the exhaust of the vehicle, Borja discloses that the dimensions of the air cleaning device may be varied as needed for a particular application. In particular, as shown in FIG. 3, section 14 of the device includes a plurality of filter chambers C, D and E and an exhaust chamber F. The chambers C, D and E are separated from one another by means of dividers/screens that have apertures therein. In this example, filter chamber C is filled with sponge-type material, chamber D is filled with activated carbon and chamber E is filled with non-treated filter material.
U.S. Pat. No. 5,503,806 to Fulmer et al. discloses a varying permeability filter. The filter is mounted in the gas generation chamber and is especially designed to filter out and entrap unwanted contaminants and by-products from the generated gas. The filter eliminates the need for the use of multiple filters because the filter has multiple regions, which are of low, intermediate and high porosity or permeability.
U.S. Patent Application Publication No. 2007/0084168 to Ashwood et al. discloses a flexible size adjustable filter. The filter includes a mixture of natural and synthetic fibers and is mounted on a rigid wire frame member. The filter having the frame member attached thereto is held within the filter housing along the side loading channels.
The remaining patents and publications, listed above but not specifically discussed, are deemed to be only of general interest and show the state of the art in air filters.
None of the prior art discussed above discloses a single multi-sectioned panel air filter with each sectioned filter portion having a different media to remove different types of contaminants from the outdoor supply air, before entering the occupied spaces of large buildings, via heating, ventilating and air conditioning systems.